I use to be a very nice person. Then I was shocked to find out being nice did not mean you were humble. I was one of the most self righteous persons I knew.
Someone once said being humble is not thinking you are worse than you are or thinking your are better than you are. It is about not thinking of yourself at all. Others have said it is thinking rightly about yourself. You who you are a child of the King. Loved. Delighted in Cherished. Blessed. Valued. Saved, righteous, forgiven, and on and on.
Humility is a trate God has to work in your life. You can pray to be humbled. It is a very courageous prayer because it usually means being stripped of all your self sufficiency, arrogance, independence, pride. But oh when you reach that place of depending on God and not yourself there is no better joy.